Grade standards and canned vegetable quality


Perhaps no one has clearly highlighted the fault lines between the food movement and processed food as Anna Zeide in the book Canned: The Rise and Fall of Consumer Confidence in the American Food Industry. Last week I reviewed the book as a whole. This week I delve further into her perspective with particular emphasis on quality of fresh and canned vegetables. I also briefly discuss the charge that agricultural research unfairly benefits industry and wealthy farmers to the disadvantage of consumers. In the next two weeks I will focus on other aspects of the topics covered in this consequential book.

Chapter 4 in Canned is all about quality and how the industry resisted grade standards for canned tomatoes specifically and vegetables in general. Canned goods have “opacity” to deal with as we can’t see into the can when we buy it like we can look at and actually handle fresh produce. I happen to be very interested in fruit and vegetable quality as it was my key area of research (1) during a 31-year career at the University of Georgia. Part of that work involved developing a better understanding of how quality of fresh fruit and vegetables is perceived during handling from farm to consumer. My lab group worked primarily with fresh blueberries, peaches, sweet onions and tomatoes. In addition, I spent the summer between my Freshman and Sophomore year in college as a worker in a Green Giant plant that canned asparagus. What I learned in my research and on the job does not exactly agree with the portrayal of quality of fruits and vegetables in Canned. For example, a key point that the author makes in her own words on canned tomato quality is that (bold quotes are directly from the book):

“Once the tomatoes reached the cannery, they would likely have been evaluated by a government-trained inspector who would grade each tomato as No. 1, No. 2 or cull according to quality.” The author’s explanation differs sharply from my personal experiences. First, “a government-trained inspector” pulls a statistical sample of the tomatoes in the field to determine the appropriate grade and not each tomato individually. Meat inspections are different as every carcass is evaluated individually for visual defects. USDA grades are generally an indication of the level of visual defects in a lot and not related to flavor or other quality attributes. I am not sure if government grades were used prior to World War II to provide a basis for payment to the grower from the processor. Grading by a government inspector introduces delays and does not fit well into a hectic harvest schedule.  Company inspectors have graded incoming vegetables for quality in most cannery operations for over 50 years.

Grading hypocrisy

Zeide sees clear hypocrisy with respect to canners using inspections in the field but not on the can label. I am skeptical that vegetable canners routinely use government inspections of raw crops in the field. With respect to fresh vegetables, my experience in the 1980s and 90s indicates that such grades were primarily used to settle disagreements between buyers and sellers. For example, if a California grower ships a load of tomatoes to the Atlanta Terminal Market and the contract calls for U.S. No. 1 tomatoes, the buyer might reject the load if it does not live up to expectations. The California shipper could then request a USDA inspection to determine if the load was truly U.S. No. 1. If the inspector sides with the shipper, the company in Atlanta would be required to pay the shipper the agreed upon price and pay the USDA the cost of the inspection. If the inspector determines that the load is not up to the standard, the shipper in California pays USDA and either negotiates a lower price from the buyer or calls around to see who else in the Atlanta area might be interested in buying the load.

If grade standards were used in the field for canning tomatoes, as suggested in Canned, it would be to estimate the amount of tomatoes to be culled on the grading line in the processing plant. Logistically, it would be difficult for a processor to declare a particular grade on a label as a statistical sample would need to be taken after cooking in the can and before labeling. Such routine inspections would be costly and probably not worth the expense to the processor and of little value to the consumer. One other point of clarification is that canning tomatoes are very different from most slicing tomatoes. Roma tomatoes, for example, are a type canning tomato. The most important quality attribute for canning tomatoes is its total-solids content.

Branding and quality

The author also expresses frustration that the consumer of canned vegetables has no indication of flavor due to the opacity of the can. As mentioned above, government inspections provide no key to the flavor of the items inside the can. Canning is a harsh processing treatment—heating in a steam retort under pressure at high temperatures for many minutes. There is very little flavor left in a canned vegetable (2) relative to one that is fresh or frozen. Canners want to make sure that their products have no off-flavors, but they are more interested in other quality characteristics such as color or texture. My interaction with food companies suggests that they are either looking to produce a product that can be sold at the lowest price or one that represents a consistent level of quality to command a price premium. At Green Giant I learned that a company could produce a top brand that represented premium quality and a brand with lower quality standards that could be sold at the lowest price.

When raw asparagus came in on a truck to the Green Giant plant, a sample was collected and taken to the grading shack. The prime characteristic of importance was woodiness which was evaluated by a very simple device. The asparagus was then unloaded, washed and hand culled to remove the sticks, obviously unacceptable spears and other undesirable material. The spears travelled through several more steps before ending up in a sealed can ready for cooking. The heating was carefully monitored to ensure the finished product was safe, particularly from botulism. The cooled cans went directly to the warehouse. If the grading shack had given that truckload the top score for low woodiness, the cans were labeled Green Giant. If not, those cans were boxed up for labelling with other brands after the season. There were three other levels of quality, based on woodiness. One of those labels was Kounty Kist. I don’t remember the other two. Contrary to the description in Canned, the brand was a clear indication of asparagus quality, and Green Giant appeared to be very protective of its label.

Industry/government collusion

The early description in Canned of prairie life in a small town with a local cannery brought back memories from when I was much younger. I grew up in a such a town, just north of the US border, in the 50s and 60s. The next town, seven miles east, also had a local cannery. My dad, a food scientist at a government-run agricultural station, worked with both canneries. My childhood was at the center of the interaction between farm, cannery and government research mentioned in the book. I followed in my father’s footsteps working as a food scientist at a larger agricultural experiment station before moving to the main university campus.

Zeide questions the value of government paying for research and extension operations, particularly as it led to the foundation of the industrialized food system—one of the purported evils of American capitalism. As a researcher I didn’t ask myself  “What have I done for the state of Georgia today?” like my extension colleagues did before they said their prayers each night. I did feel proud of my work, however, as I believed that it was contributing to the economic stability of the state and to a greater knowledge about maintaining quality of fresh fruits and vegetables as delivered to the market. According to Zeide I am delusional as apparently are my friends in extension.

The food movement has asked many important questions that those of us associated with the food research should consider. Members of the movement do not have all the answers, however, and would do well to listen at least as much as they talk. Neither should food scientists blindly accept the pronouncements of an industry that markets to the hopes, fears and biases of the American public. Problems with the American food system will not be solved by polemics and proclamations of certainty about food and nutrition. Issues about the foods we eat and the nourishment they provide are much more complex than what we read about in a sensationalized media environment. Anna Zeide has outlined clear differences in perspective between the movement and the industry. Food scientists must listen and respond. I contend that there is a middle ground that can be pursued to provide a more bountiful and healthy food supply.


Next week: The food movement vs. Big Food

(1) Shewfelt, R.L., 1999. What is quality? Postharvest Biology and Technology 15:197-200.

(2) A tomato is a fruit botanically, but common usage considers it a vegetable as it typically is eaten as part of the main course or as an ingredient in a main entrée.

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